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Primary Examiner—James J. Groody
Assistant Examiner—Jeffrey S. Murrell
[57] ABSTRACT
A digital video field identification system includes video signals formatted in blocks of video symbols in repetitive data segments with each data segment including a synchronizing signal character. One data segment includes a field timing signal. A field reference data segment which includes the field timing signal is developed at the receiver. Each data segment is compared with the field reference data segment and the number of symbol errors is accumulated for each data segment. The data segment exhibiting the least number of symbol errors is identified as the field timing segment. A confidence counter stabilizes the identification of said one data segment. The video signals are precoded in modulo N form to enable NTSC co-channel interference rejection in the receiver by a linear filter. The linear filter undesirably reduces the S/N ratio by 3dB. A selection circuit is included for bypassing the linear filter (for the video data) based upon the errors developed in the signal paths with and without the linear filter.
18 Claims, 3 Drawing Sheets
